While a deck can add to the attractiveness and utility of your home, it is far from a maintenance free addition. The proper maintenance is necessary to protect the life and appearance of your deck.
It is a common misconception that pressure treated wood, which is the wood most often used for decks, requires little maintenance.
The pressure treating process involves the injection of chromated copper arsenate into the wood cells. Copper acts as a fungicide, while arsenic is an insecticide.
While these chemicals protect against insects and fungus, they leave the surface vulnerable to the effects of rain and sun. Even redwood and cedar, two other common woods used for decks, can be damaged by the elements.
One of the most common consequences of exposure to rain and sun is cracked wood. As water penetrates the wood cells, they expand. When the water evaporates, the wood cells begin to shrink.
Repetitive expansion and contraction of the wood ultimately results in cracked boards. Newly installed wood should be protected as soon as possible. It is not necessary to allow the wood to "weather" or "season".
Unprotected exposure to the elements, for even a few weeks, can result in damage to the wood.
Preventing water from penetrating the wood surface can greatly extend the life of the wood, as well as add to its attractiveness.
There are many products on the market for protecting exterior wood surfaces. These range from paints and stains, to clear wood preservatives and water repellents.
As is the case when applying any type of coating, proper preparation is essential. A clean, dry surface is necessary for proper adhesion.
Proper preparation involves removing dirt, mildew, stains and wood fibers damaged by UV light. If these deposits are not removed prior to applying a finish, both adhesion and appearance of the finish may be diminished.
Many products are available for cleaning decks and wood siding. Most can be applied with a pump type sprayer or a mop.
Most products on the market contain either sodium hypochlorite (chlorine bleach) or oxalic acid, both of which can damage wood fibers and actually lead to premature coating failure.
The most effective protection for decks occurs when the product penetrates the surface. Film forming products, such as paints, lay on the surface of the wood and have a tendency to blister, peel, and mar when used on horizontal surfaces.
The three most common products for protecting decks are water repellents (also called water sealers), clear wood finishes, and semi-transparent stains.
The first two products are generally clear, penetrating coatings. Semi-transparent stains work much like water repellents, but also contain pigments to impart color to the wood surface.
When selecting a coating for wood surfaces, three characteristics should be considered: water repellency, mildew resistance, and weathering resistance. Water repellency prevents moisture from penetrating the wood fibers and causing the expansion and contraction of those fibers.
Mildew resistance will retard the growth of damaging mold spores. The higher quality products contain UV blockers, which not only extend the life of the coating, but also prevent UV damage to the wood fibers. UV damage usually causes a graying of wood fibers.
With proper care, your deck can be an attractive and valuable addition to your home for years. Choosing a contractor with the knowledge and skills to properly prepare the surface and apply the proper products is the first step in protecting the life and appearance of your deck.